Here's a real simple experiment. Google "bicycle helmets". Click on "Shopping" and sort by price. Look for ones that are similar to what you'd see in a professional road race. The most expensive ones are the ones that the pros are wearing this season. Look for images of professional road racers from a couple of years ago. Those helmets are now on close-out.

One could even argue that the most expensive helmets fall are apt to fall apart quicker, as they have more ventilation (more holes), structurally less strong than fewer holes. A current model Giro Aeon helmet suggested retail is $200.

The marketing: You wanted a lighter helmet, a cooler helmet, a better helmet—so we created one. Starting with a full roster of our best features, we optimized every component in the Aeon™ including the shape of the helmet itself, reducing weight by 28 percent compared with its predecessor. We also sculpted massive vents with interior channeling for best-in-class cooling power and integrated the adjustability and comfort of Roc LocŪ 5, for a luxurious feel with all the performance you need.

The cheapest helmet I found using Google Shopping is under $10. It passes the same tests as the $200 helmet. If it fits you well, there's no safety reasoon not to buy it over the $200 helmet. You will find, however, that spending more gets you better adjustability, and fit is more important than any other factor. You may also find one helmet to have better ventilation than another. The last thing is looks: if you don't like the way it looks on you, you're less likely to wear it.

If more expensive helmets lasted longer than cheaper ones, wouldn't they advertise that?